The study is planned as a blinded, randomized controlled study with four parallel arms. 120 OLP patients with symptoms form the mucous membranes are included in the study and will receive nystatin or fluocinolone treatment depending on positive or negative diagnosis of candidosis. In addition, they will be assigned to either the probiotic (A) or the placebo group (B) by randomization. The groups will be encouraged to take three tablets per day (morning, noon and evening)for eight weeks. The lozenges containseither two strains of the probiotic bacterium L. reuteri (A) or placebo (B). Cytosmears, saliva sample, and saline mouth wash will be taken at baseline, after the treatment period and at follow-up visits at 8, 16, 24 weeks and 1 year. Salivary counts of the probiotic strains, the clinical manifestations and symptoms associated to OLP will be recorded.